In reply to Strongbeard:
I get this with my Salomon XA trail shoes if I haven't worn them in a while. It's odd, as the blisters don't seem to cause me a great deal of pain, and once I've been running a few days consistently the skin toughens up and no longer blisters. I'm not sure that will happen for you, as you say it's having an impact on your longer runs (I never do more than 8mi anyway!).
I can't comment on the chaff stick, never used it but it could be worth a go. What works for me is Tensoplast tape, the 7.5cm width stuff. I've used it successfully for years in preventing blisters in myself and others (I was a medic with a military unit which seemed to specialise in giving people nasty blisters). It's a conforming elastic adhesive bandage and it's very sticky, so be careful when removing and don't put it over a formed blister unless you really, really need to i.e. to finish a race. Take a 6-8in strip under your arch with the hot-spot in the middle and bring each side up over the top of your foot. Make sure the skin is clean and dry first, and once the tape is on do 5min of gentle massage / warming over it to ensure you get a really good bond. You don't want the tape rolling in at the edges, but if that happens you can trim that section away.
As wbo says above, lay off the compeed. It's a sophisticated hydrocolloid dressing, and works excellently for healing in a clean environment. However in my experience if you plan to keep running it makes things worse, becoming a larger pressure point and a reservoir for infection.
Clearly though this is literally just a sticking plaster; try to get to a reputable fell-runner-type shop and see if they can help get you into some comfy shoes. Lakes Climber used to be excellent at fitting shoes, wouldn't know who to go to now. Having had some experience of gait analysis, I'd say it's probably meaningless without a very knowledgeable and experienced fitter.
Post edited at 11:42